| 摘要 |
<p>PURPOSE:To make it possible to control rotations of a video head drum not only in normal-speed playback mode but also in slow-motion playback time, by using a control signal as a reference signal. CONSTITUTION:On the control track part of video tape 1, signals (n) times as high as a half vertical synchronizing frequency are recorded differing in amplitude and in accordance with a speed for reproduction, control signals are detected by being classified by amplitude to obtain a reference signal. This reference signal is compared with a detection signal from video head drum 6 and the error signal controls rotations of video head drum 6. Consequently, the speed of video tape 1 synchronizes accurately with that of video head drum 6 in 1/n-speed, i.e. slowmotion playback mode, let along in 1/1-speed, i.e. normal-speed playback mode, so that a stable picture can be obtained.</p> |
